All concrete versions of this "subject supposed to believe" (from small children for whose sake parents pretend to believe in Santa Claus, to the "ordinary working people" for whose sake Communist intellectuals pretend to believe in Socialism) are stand-ins for the big Other. So, what one should answer to the conservative platitude according to which every honest man has a profound need to believe in something, is that every honest man has a profound need to find another subject who would believe in his place…- Slavoj Zizek, "The Interpassive Subject"
The two notions, that of the subject supposed to believe and that of the subject supposed to know, are not symmetrical since belief and knowledge themselves are not symmetrical: at its most radical, the status of the (Lacanian) big Other qua symbolic institution, is that of belief (trust), not that of knowledge, since belief is symbolic and knowledge is real (the big Other involves, and relies on, a fundamental "trust"). The two subjects are thus not symmetrical since belief and knowledge themselves are not symmetrical: belief is always minimally "reflective," a "belief in the belief of the other" ("I still believe in Communism" is the equivalent of saying "I believe there are still people who believe in Communism"), while knowledge is precisely not knowledge about the fact that there is another who knows. For this reason, I can BELIEVE through the other, but I cannot KNOW through the other. That is to say, due to the inherent reflectivity of belief, when another believes in my place, I myself believe through him; knowledge is not reflective in the same way, i.e. when the other is supposed to know, I do not know through him.
Belief can only thrive in the shadowy domain between outright falsity and positive truth.
And is the primordial version of this substitution by means of which "somebody else does it for me," not the very substitution of a signifier for the subject? In such a substitution resides the basic, constitutive feature of the symbolic order: a signifier is precisely an object-thing which substitutes me, which acts in my place. The so-called primitive religions in which another human being can take upon himself my suffering, my punishment (but also my laughter, my enjoyment…), i.e. in which one can suffer and pay the price for a sin through the Other (up to prayer wheels which do the praying for you), are not as stupid and "primitive" as they may seem — they harbor a momentous liberating potential. By way of surrendering my innermost content, inclusive of my dreams and anxieties, to the Other, a space opens up in which I am free to breathe: when the Other laughs for me, I am free to take a rest; when the Other is sacrificed instead of me, I am free to go on living with the awareness that I did pay for my guilt; etc.etc. The efficiency of this operation of substitution resides in the Hegelian reflective reversal: when the Other is sacrificed for me, I sacrifice myself through the Other; when the Other acts for me, I myself act through the Other; when the Other enjoys for me, I myself enjoy through the Other. Like, in the good old joke about the difference between Soviet-style bureaucratic Socialism and the Yugoslav self-management Socialism: in Russia, members of the nomenklatura, the representatives of the ordinary people, drive themselves in expensive limousines, while in Yugoslavia, ordinary people themselves ride in limousines through their representatives. This liberating potential of mechanical rituals is also clearly discernible in our modern experience: every intellectual knows of the redeeming value of being temporarily subjected to the military drill, to the requirements of a "primitive" physical job, or to some similar externally regulated labour — the very awareness that the Other regulates the process in which I participate, sets my mind free to roam, since I know I am not involved. The Foucauldian motif of the interconnection between discipline and subjective freedom thus appears in a different light: by submitting myself to some disciplinatory machine, I, as it were, transfer to the Other the responsibility to maintain the smooth run of things, and thus gain the precious space in which to exercise my freedom…
The one who originally "does it for me" is the signifier itself in its external materiality, from the "canned prayer" in the Tibetan prayer wheel to the "canned laughter" on our TV: the basic feature of the symbolic order qua "big Other," is that it is never simply a tool or means of communication, since it "decenters" the subject from within, in the sense of accomplishing his act for him. This gap between the subject and the signifier which "does it for him," is clearly discernible in common everyday experience: when a person slips, another person standing next to him and merely observing the accident, can accompany it with "Oops!" or something similar. The mystery of this everyday occurrence is that, when the other does it for me, instead of me, the symbolic efficiency of it is exactly the same as in the case of my doing it directly. Therein resides the paradox of the notion of the "performative," or speech act: in the very gesture of accomplishing an act by way of uttering words, I am deprived of authorship, the "big Other" (the symbolic institution) speaks through me. It is no wonder then, that there is something puppet-like about the persons whose professional function is tessentially performative (judges, kings…): they are reduced to a living embodiment of the symbolic institution, i.e. their sole duty is to "dot the i's" mechanically, to confer on some content elaborated by others, the institutional cachet. The later Lacan is fully justified in reserving the term "act" for something much more suicidal and real than a speech act.
This mystery of the symbolic order is exemplified by the enigmatic status of what we call "politeness": when, upon meeting an acquaintance, I say "Glad to see you! How are you today?", it is clear to both of us that, in a way, I "do not mean it seriously" (if my partner suspects that I am really interested, he may even be unpleasantly surprised, as though I were aiming at something too intimate and of no concern to me — or, to paraphrase the old Freudian joke, "Why are you saying you're glad to see me, when you're really glad to see me!?"). However, it would nonetheless be wrong to designate my act as simply "hypocritical," since, in another way, I do mean it: the polite exchange does establish a kind of pact between the two of us; in the same sense as I do "sincerely" laugh through the canned laughter (the proof of it being the fact that I effectively do "feel relieved" afterwards).
If we radicalize in this way the relationship of substitution (i.e. the first aspect of the notion of fetishism), then the connection between the two aspects, the opposition "persons versus things," their relation of substitution ("things instead of people," or one person instead of another, or a signifier instead of the signified…), and the opposition "structure versus one of its elements," becomes clear: the differential/formal structure occluded by the element-fetish, can only emerge if the gesture of substitution has already occurred. In other words, the structure is always, by definition, a signifying structure, a structure of signifiers which are substituted for the signified content, not a structure of the signified. For the differential/formal structure to emerge, the real has to redouble itself in the symbolic register; a reduplicatio has to occur, on account of which things no longer count as what they directly "are," but only with regard to their symbolic place. This primordial substitution of the big Other, the Symbolic Order, for the Real of the immediate life-substance (in Lacanian terms: of A — le grand Autre — for J — jouissance), gives rise to $, to the "barred subject" who is then "represented" by the signifiers, i.e. on whose behalf signifiers "act," who acts through signifiers…